Going from web development to creating your own semiconductor lab to understand the solid state physics of transistors enough to make one will not only take more than a year, it's also silly.

You may as well learn C and the guts of microprocessors if you're really concerned about how a computer actually operates.

Web development really just treats the whole of the internet as one big computer, and the dev formats interesting content nicely for the screen of the user, which is ultimately about presenting useful data. There's probably little incentive to take a "year off" to try and understand the whole thing from the physics to the electronics to the logic to the anthopology and philosophy of computation - it's too big a field and something you'll be spending the rest of your life doing. Plus even in a year, starting from scratch, even with 8-bit kits or transistors, any computer you make when compared to modern machines won't really even do anything. Imo you'd be better off getting a ZX Spectrum, a cassette drive, a copy of Manic Miner, and enjoying watching the 48kb of it load into the machine, then pouring over the code. Or even Elite on the BBC Microcomputer. Understanding these few thousand kilobytes of machine code and how they interact with the machines is easily food for thought for a year. Then just multiply that by a few thousand in terms of resolution, bandwidth, speed, and you'll understand modern computation better.

Or just go travelling for a year and don't think about computers...